Radio-unlicensed multi-channel access for low-radio frequency-capable user equipment

ABSTRACT

New radio (NR) unlicensed (NR-U) multi-channel access is disclosed for low-radio frequency (RF)-capable user equipment (UE). A base station may enable multi-channel access when single operator operations cannot be guaranteed within a shared communication spectrum. The primary and secondary channels are defined within the shared communication channel. The base station may then transmit a configuration message to one or more low-RF UEs that identifies the charnels and directs the UEs to monitor the primary channel for a successful listen before talk (LBT) indicator. The base station performs an LBT procedure on the primary channel and the secondary channel and signals the low-RF UEs to re-tune to the secondary channel for communication during a current transmission opportunity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 62/737,552, entitled, “NR-U MULTI-CHANNEL ACCESS FORLOW-RF-CAPABLE UES,” filed on Sep. 27, 2018, which is expresslyincorporated by reference herein in its entirety.

BACKGROUND Field

Aspects of the present disclosure relate generally to wirelesscommunication systems, and more particularly, to new radio (NR)unlicensed (NR-U) multi-channel access for low-radio frequency(RF)-capable user equipment (UE).

Background

Wireless communication networks are widely deployed to provide variouscommunication services such as voice, video, packet data, messaging,broadcast, and the like. These wireless networks may be multiple-accessnetworks capable of supporting multiple users by sharing the availablenetwork resources. Such networks, which are usually multiple accessnetworks, support communications for multiple users by sharing theavailable network resources. One example of such a network is theUniversal Terrestrial Radio Access Network (UTRAN). The UTRAN is theradio access network (RAN) defined as a part of the Universal MobileTelecommunications System (UMTS), a third generation (3G) mobile phonetechnology supported by the 3rd Generation Partnership Project (3GPP).Examples of multiple-access network formats include Code DivisionMultiple Access (CDMA) networks, Time Division Multiple Access (TDMA)networks, Frequency Division Multiple Access (FDMA) networks, OrthogonalFDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA) networks.

A wireless communication network may include a number of base stationsor node Bs that can support communication for a number of userequipments (UEs). A UE may communicate with a base station via downlinkand uplink. The downlink (or forward link) refers to the communicationlink from the base station to the UE, and the uplink (or reverse link)refers to the communication link from the UE to the base station.

A base station may transmit data and control information on the downlinkto a UE and/or may receive data and control information on the uplinkfrom the UE. On the downlink, a transmission from the base station mayencounter interference due to transmissions from neighbor base stationsor from other wireless radio frequency (RE) transmitters. On the uplink,a transmission from the UE may encounter interference from uplinktransmissions of other UEs communicating with the neighbor base stationsor from other wireless RE transmitters. This interference may degradeperformance on both the downlink and uplink.

As the demand for mobile broadband access continues to increase, thepossibilities of interference and congested networks grows with more UEsaccessing the long-range wireless communication networks and moreshort-range wireless systems being deployed in communities. Research anddevelopment continue to advance wireless technologies not only to meetthe growing demand for mobile broadband access, but to advance andenhance the user experience with mobile communications.

SUMMARY

In one aspect of the disclosure, a method of wireless communicationincludes enabling, by a base station, multi-channel access when singleoperator operations cannot be guaranteed within a shared communicationspectrum, defining, by the base station, a primary channel and asecondary channels within the shared communication channel,transmitting, by the base station, a configuration message to one ormore low-radio frequency (RF) user equipments (UEs), wherein theconfiguration message configures the one or more low-RF UEs to monitorthe primary channel for a successful listen before talk (LBT) indicator,performing, by the base station, an LBT procedure on the primary channeland the secondary channel, and signaling, by the base station, the oneor more low-RF UEs on the primary channel to re-tune to the secondarychannel for communication during a current transmission opportunity inresponse to success of the LBT procedure on the secondary channel.

In an additional aspect of the disclosure, a method of communicationincludes receiving, by a low-RF UE, a configuration message from aserving base station, monitoring, by the low-RE UE, the primary channelfor a successful LBT indicator in response to the configuration message,and receiving, by the low-RF UE, a re-tuning signal on the primarychannel, wherein the re-tuning signal instructs the low-RF UE to re-tuneto a secondary channel for communications during the currenttransmission opportunity.

In an additional aspect of the disclosure, an apparatus configured forwireless communication includes means for enabling, by a base station,multi-channel access when single operator operations cannot beguaranteed within a shared communication spectrum, means for defining,by the base station, a primary channel and a secondary channels withinthe shared communication channel, means for transmitting, by the basestation, a configuration message to one or more low-RF UEs, wherein theconfiguration message configures the one or more low-RF UEs to monitorthe primary channel for a successful LBT indicator, means forperforming, by the base station, an LBT procedure on the primary channeland the secondary channel, and means for signaling, by the base station,the one or more low-RF UEs on the primary channel to re-tune to thesecondary channel for communication during a current transmissionopportunity in response to success of the LBT procedure on the secondarychannel.

In an additional aspect of the disclosure, an apparatus configured forwireless communication includes means for receiving, by a low-RF UE, aconfiguration message from a serving base station, means for monitoring,by the low-RF UE, the primary channel for a successful LBT indicator inresponse to the configuration message, and means for receiving, by thelow-RF UE, a re-tuning signal on the primary channel, wherein there-tuning signal instructs the low-RF UE to re-tune to a secondarychannel for communications during the current transmission opportunity.

In an additional aspect of the disclosure, a non-transitorycomputer-readable medium having program code recorded thereon. Theprogram code further includes code to enable, by a base station,multi-channel access when single operator operations cannot beguaranteed within a shared communication spectrum, code to define, bythe base station, a primary channel and a secondary channels within theshared communication channel, code to transmit, by the base station, aconfiguration message to one or more low-RF UEs, wherein theconfiguration message configures the one or more low-RF UEs to monitorthe primary channel for a successful LBT indicator, code to perform, bythe base station, an LBT procedure on the primary channel and thesecondary channel, and code to signal, by the base station, the one ormore low-RF UEs on the primary channel to re-tune to the secondarychannel for communication during a current transmission opportunity inresponse to success of the LBT procedure on the secondary channel.

In an additional aspect of the disclosure, a non-transitorycomputer-readable medium having program code recorded thereon. Theprogram code further includes code to receive, by a low-RF UE, aconfiguration message from a serving base station, code to monitor, bythe low-RF UE, the primary channel for a successful LBT indicator inresponse to the configuration message, and code to receive, by thelow-RF UE, a re-tuning signal on the primary channel, wherein there-tuning signal instructs the low-RF UE to re-tune to a secondarychannel for communications during the current transmission opportunity.

In an additional aspect of the disclosure, an apparatus configured forwireless communication is disclosed. The apparatus includes at least oneprocessor, and a memory coupled to the processor. The processor isconfigured to enable, by a base station, multi-channel access whensingle operator operations cannot be guaranteed within a sharedcommunication spectrum, to define, by the base station, a primarychannel and a secondary channels within the shared communicationchannel, to transmit, by the base station, a configuration message toone or more low-RF UEs, wherein the configuration message configures theone or more low-RF UEs to monitor the primary channel for a successfulLBT indicator, to perform, by the base station, an LBT procedure on theprimary channel and the secondary channel, and to signal, by the basestation, the one or more low-RF UEs on the primary channel to re-tune tothe secondary channel for communication during a current transmissionopportunity in response to success of the LBT procedure on the secondarychannel.

In an additional aspect of the disclosure, an apparatus configured forwireless communication is disclosed. The apparatus includes at least oneprocessor, and a memory coupled to the processor. The processor isconfigured to receive, by a low-RF UE, a configuration message from aserving base station, to monitor, by the low-RF UE, the primary channelfor a successful LBT indicator in response to the configuration message,and to receive, by the low-RF UE, a re-tuning signal on the primarychannel, wherein the re-tuning signal instructs the low-RF UE to re-tuneto a secondary channel for communications during the currenttransmission opportunity.

The foregoing has outlined rather broadly the features and technicaladvantages of examples according to the disclosure in order that thedetailed description that follows may be better understood. Additionalfeatures and advantages will be described hereinafter. The conceptionand specific examples disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present disclosure. Such equivalent constructions do notdepart from the scope of the appended claims. Characteristics of theconcepts disclosed herein, both their organization and method ofoperation, together with associated advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. Each of the figures is provided for the purpose ofillustration and description, and not as a definition of the limits ofthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the presentdisclosure may be realized by reference to the following drawings. Inthe appended figures, similar components or features may have the samereference label. Further, various components of the same type may bedistinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

FIG. 1 is a block diagram illustrating details of a wirelesscommunication system.

FIG. 2 is a block diagram illustrating a design of a base station and aUE configured according to one aspect of the present disclosure.

FIG. 3 is a block diagram illustrating a wireless communication systemincluding base stations that use directional wireless beams.

FIGS. 4A and 4B are block diagrams illustrating NR-U networks.

FIGS. 5A and 5B are block diagrams illustrating example blocks executedto implement aspects of the present disclosure.

FIGS. 6A-6D are block diagrams illustrating multi-channel communicationsbetween a base station and a low-RF UE each configured according toaspects of the present disclosure.

FIG. 7 is a block diagram illustrating an example base stationconfigured according to one aspect of the present disclosure.

FIG. 8 is a block diagram illustrating an example UE configuredaccording to one aspect of the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below, in connection with theappended drawings, is intended as a description of variousconfigurations and is not intended to limit the scope of the disclosure.Rather, the detailed description includes specific details for thepurpose of providing a thorough understanding of the inventive subjectmatter. It will be apparent to those skilled in the art that thesespecific details are not required in every case and that, in someinstances, well-known structures and components are shown in blockdiagram form for clarity of presentation.

This disclosure relates generally to providing or participating inauthorized shared access between two or more wireless communicationssystems, also referred to as wireless communications networks. Invarious embodiments, the techniques and apparatus may be used forwireless communication networks such as code division multiple access(CDMA) networks, time division multiple access (TDMA) networks,frequency division multiple access (FDMA) networks, orthogonal FDMA(OFDMA) networks, single-carrier FDMA (SC-FDMA) networks, LTE networks,GSM networks, 5^(th) Generation (5G) or new radio (NR) networks, as wellas other communications networks. As described herein, the terms“networks” and “systems” may be used interchangeably.

An OFDMA network may implement a radio technology such as evolved UTRA(E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM and thelike. UTRA, E-UTRA, and Global System for Mobile Communications (GSM)are part of universal mobile telecommunication system (UMTS). Inparticular, long term evolution (LTE) is a release of UMTS that usesE-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documentsprovided from an organization named “3rd Generation Partnership Project”(3GPP), and cdma2000 is described in documents from an organizationnamed “3rd Generation. Partnership Project 2” (3GPP2). These variousradio technologies and standards are known or are being developed. Forexample, the 3rd Generation Partnership Project (3GPP) is acollaboration between groups of telecommunications associations thataims to define a globally applicable third generation (3G) mobile phonespecification. 3GPP long term evolution (LTE) is a 3GPP project whichwas aimed at improving the universal mobile telecommunications system(UMTS) mobile phone standard. The 3GPP may define specifications for thenext generation of mobile networks, mobile systems, and mobile devices.The present disclosure is concerned with the evolution of wirelesstechnologies from LTE, 4G, 5G, NR, and beyond with shared access towireless spectrum between networks using a collection of new anddifferent radio access technologies or radio air interfaces.

In particular, 5G networks contemplate diverse deployments, diversespectrum, and diverse services and devices that may be implemented usingan OFDM-based unified, air interface. In order to achieve these goals,further enhancements to LTE and LTE-A are considered in addition todevelopment of the new radio technology for 5G NR networks. The 5G NRwill be capable of scaling to provide coverage (1) to a massive Internetof things (IoTs) with an ultra-high density (e.g., ˜1 M nodes/km²),ultra-low complexity (e.g., ˜10 s of bits/sec), ultra-low energy (e.g.,˜10+ years of battery life), and deep coverage with the capability toreach challenging locations; (2) including mission-critical control withstrong security to safeguard sensitive personal, financial, orclassified information, ultra-high reliability (e.g., ˜99.9999%reliability), ultra-low latency (e.g., ˜1 ms), and users with wideranges of mobility or lack thereof; and (3) with enhanced mobilebroadband including extreme high capacity (e.g., ˜10 Tbps/km²), extremedata rates (e.g., multi-Gbps rate, 100+ Mbps user experienced rates),and deep awareness with advanced discovery and optimizations.

The 5G NR may be implemented to use optimized OFDM-based waveforms withscalable numerology and transmission time interval (TTI); having acommon, flexible framework to efficiently multiplex services andfeatures with a dynamic, low-latency time division duplex(TDD)/frequency division duplex (FDD) design; and with advanced wirelesstechnologies, such as massive multiple input, multiple output (MIMO),robust millimeter wave (mmWave) transmissions, advanced channel coding,and device-centric mobility. Scalability of the numerology in 5G NR,with scaling of subcarrier spacing, may efficiently address operatingdiverse services across diverse spectrum and diverse deployments. Forexample, in various outdoor and macro coverage deployments of less than3 GHz FDD/TDD implementations, subcarrier spacing may occur with 15 kHz,for example over 1, 5, 10, 20 MHz, and the like bandwidth. For othervarious outdoor and small cell coverage deployments of TDD greater than3 GHz, subcarrier spacing may occur with 30 kHz over 80/100 MHzbandwidth. For other various indoor wideband implementations, using aTDD over the unlicensed portion of the 5 GHz band, the subcarrierspacing may occur with 60 kHz over a 160 MHz bandwidth. Finally, forvarious deployments transmitting with mmWave components at a TDD of 28GHz, subcarrier spacing may occur with 120 kHz over a 500 MHz bandwidth.

The scalable numerology of the 5G NR facilitates scalable TTI fordiverse latency and quality of service (QoS) requirements. For example,shorter TTI may be used for low latency and high reliability, whilelonger TTI may be used for higher spectral efficiency. The efficientmultiplexing of long and short TTIs to allow transmissions to start onsymbol boundaries. 5G NR also contemplates a self-contained integratedsubframe design with uplink/downlink scheduling information, data, andacknowledgement in the same subframe. The self-contained integratedsubframe supports communications in unlicensed or contention-basedshared spectrum, adaptive uplink/downlink that may be flexiblyconfigured on a per-cell basis to dynamically switch between uplink anddownlink to meet the current traffic needs.

Various other aspects and features of the disclosure are furtherdescribed below. It should be apparent that the teachings herein may beembodied in a wide variety of forms and that any specific structure,function, or both being disclosed herein is merely representative andnot limiting. Based on the teachings herein one of an ordinary level ofskill in the art should appreciate that an aspect disclosed herein maybe implemented independently of any other aspects and that two or moreof these aspects may be combined in various ways. For example, anapparatus may be implemented or a method may be practiced using anynumber of the aspects set forth herein. In addition, such an apparatusmay be implemented or such a method may be practiced using otherstructure, functionality, or structure and functionality in addition toor other than one or more of the aspects set forth herein. For example,a method may be implemented as part of a system, device, apparatus,and/or as instructions stored on a computer readable medium forexecution on a processor or computer. Furthermore, an aspect maycomprise at least one element of a claim.

FIG. 1 is a block diagram illustrating 5G network 100 including variousbase stations and UEs configured according to aspects of the presentdisclosure. The 5G network 100 includes a number of base stations 105and other network entities. A base station may be a station thatcommunicates with the UEs and may also be referred to as an evolved nodeB (eNB), a next generation eNB (gNB), an access point, and the like.Each base station 105 may provide communication coverage for aparticular geographic area. In 3GPP, the term “cell” can refer to thisparticular geographic coverage area of a base station and/or a basestation subsystem serving the coverage area, depending on the context inwhich the term is used.

A base station may provide communication coverage for a macro cell or asmall cell, such as a pico cell or a femto cell, and/or other types ofcell. A macro cell generally covers a relatively, large geographic area(e.g., several kilometers in radius) and may allow unrestricted accessby UEs with service subscriptions with the network provider. A smallcell, such as a pico cell, would generally cover a relatively smallergeographic area and may allow unrestricted access by UEs with servicesubscriptions with the network provider. A small cell, such as a femtocell, would also generally cover a relatively small geographic area(e.g., a home) and, in addition to unrestricted access, may also providerestricted access by UEs having an association with the femto cell(e.g., UEs in a closed subscriber group (CSG), UEs for users in thehome, and the like). A base station for a macro cell may be referred toas a macro base station. A base station for a small cell may be referredto as a small cell base station, a pico base station, a femto basestation or a home base station. In the example shown in FIG. 1 , thebase stations 105 d and 105 e are regular macro base stations, whilebase stations 105 a-105 c are macro base stations enabled with one of 3dimension (3D), full dimension (FD), or massive MIMO. Base stations 105a-105 c take advantage of their higher dimension MIMO capabilities toexploit 3D beamforming in both elevation and azimuth beamforming toincrease coverage and capacity. Base station 105 f is a small cell basestation which may be a home node or portable access point. A basestation may support one or multiple (e.g., two, three, four, and thelike) cells.

The 5G network 100 may support synchronous or asynchronous operation.For synchronous operation, the base stations may have similar frametiming, and transmissions from different base stations may beapproximately aligned in time. For asynchronous operation, the basestations may have different frame timing, and transmissions fromdifferent base stations may not be aligned in time.

The UEs 115 are dispersed throughout the wireless network 100, and eachUE may be stationary or mobile. A UE may also be referred to as aterminal, a mobile station, a subscriber unit, a station, or the like. AUE may be a cellular phone, a personal digital assistant (PDA), awireless modem, a wireless communication device, a handheld device, atablet computer, a laptop computer, a cordless phone, a wireless localloop (WLL) station, or the like. In one aspect, a UE may be a devicethat includes a Universal integrated Circuit Card (UICC). In anotheraspect, a UE may be a device that does not include a UICC. In someaspects, UEs that do not include UICCs may also be referred to asinternet of everything (IoE) or internet of things (IoT) devices. UEs115 a-115 d are examples of mobile smart phone-type devices accessing 5Gnetwork 100 A UE may also be a machine specifically configured forconnected communication, including machine type communication (MTC),enhanced MTC (eMTC), narrowband IoT (NB-IoT) and the like. UEs 115 e-115k are examples of various machines configured for communication thataccess 5G network 100. A UE may be able to communicate with any type ofthe base stations, whether macro base station, small cell, or the like.In FIG. 1 , a lightning bolt (e.g., communication links) indicateswireless transmissions between a UE and a serving base station, which isa base station designated to serve the UE on the downlink and/or uplink,or desired transmission between base stations, and backhaultransmissions between base stations.

In operation at 5G network 100, base stations 105 a-105 c serve UEs 115a and 115 b using 3D beamforming and coordinated spatial techniques,such as coordinated multipoint (CoMP) or multi-connectivity. Macro basestation 105 d performs backhaul communications with base stations 105a-105 c, as well as small cell, base station 105 f. Macro base station105 d also transmits multicast services which are subscribed to andreceived by UEs 115 c and 115 d. Such multicast services may includemobile television or stream video, or may include other services forproviding community information, such as weather emergencies or alerts,such as Amber alerts or gray alerts.

5G network 100 also support mission critical communications withultra-reliable and redundant links for mission critical devices, such UE115 e, which is a drone. Redundant communication links with UE 115 einclude from macro base stations 105 d and 105 e, as well as small cellbase station 105 f. Other machine type devices, such as UE 115 f(thermometer), UE 115 g (smart meter), and UE 115 h (wearable device)may communicate through 5G network 100 either directly with basestations, such as small cell base station 105 f, and macro base station105 e, or in multi-hop configurations by communicating with another userdevice which relays its information to the network, such as UE 115 fcommunicating temperature measurement information to the smart meter, UE115 g, which is then reported to the network through small cell basestation 105 f. 5G network 100 may also provide additional networkefficiency through dynamic, low-latency TDD/FDD communications, such asin a vehicle-to-vehicle (V2V) mesh network between UEs 115 i-115 kcommunicating with macro base station 105 e.

FIG. 2 shows a block diagram of a design of a base station 105 and a UE115, which may be one of the base station and one of the UEs in FIG. 1 .At the base station 105, a transmit processor 220 may receive data froma data source 212 and control information from a controller/processor240. The control information may be for the PBCH, PCFICH, PHICH, PDCCH,EPDCCH, MPDCCH etc. The data may be for the PDSCH, etc. The transmitprocessor 220 may process (e.g., encode and symbol map) the data andcontrol information to obtain data symbols and control symbols,respectively. The transmit processor 220 may also generate referencesymbols, e.g., for the PSS, SSS, and cell-specific reference signal. Atransmit (TX) multiple-input multiple-output (MIMO) processor 230 mayperform spatial processing (e.g., preceding) on the data symbols, thecontrol symbols, and/or the reference symbols, if applicable, and mayprovide output symbol streams to the modulators (MODs) 232 a through 232t. Each modulator 232 may process a respective output symbol stream(e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator232 may further process (e.g., convert to analog, amplify, filter, andupconvert) the output sample stream to obtain a downlink signal.Downlink signals from modulators 232 a through 232 t may be transmittedvia the antennas 234 a through 234 t, respectively.

At the UE 115, the antennas 252 a through 252 r may receive the downlinksignals from the base station 105 and may provide received signals tothe demodulators (DEMODs) 254 a through 254 r, respectively. Eachdemodulator 254 may condition (e.g., filter, amplify, downconvert, anddigitize) a respective received signal to obtain input samples. Eachdemodulator 254 may further process the input samples (e.g., for OFDM,etc.) to obtain received symbols. A MIMO detector 256 may obtainreceived symbols from all the demodulators 254 a through 254 r, performMIMO detection on the received symbols if applicable, and providedetected symbols. A receive processor 258 may process (e.g., demodulate,deinterleave, and decode) the detected symbols, provide decoded data forthe UE 115 to a data sink 260, and provide decoded control informationto a controller/processor 280.

On the uplink, at the UE 115, a transmit processor 264 may receive andprocess data (e.g., for the PUSCH) from a data source 262 and controlinformation (e.g., for the PUCCH) from the controller/processor 280. Thetransmit processor 264 may also generate reference symbols for areference signal. The symbols from the transmit processor 264 may beprecoded by a TX MIMO processor 266 if applicable, further processed bythe modulators 254 a through 254 r (e.g., for SC-FDM, etc.), andtransmitted to the base station 105. At the base station 105, the uplinksignals from the UE 115 may be received by the antennas 234, processedby the demodulators 232, detected by a MIMO detector 236 if applicable,and further processed by a receive processor 238 to obtain decoded dataand control information sent by the UE 115. The processor 238 mayprovide the decoded data to a data sink 239 and the decoded controlinformation to the controller/processor 240.

The controllers/processors 240 and 280 may direct the operation at thebase station 105 and the UE 115, respectively. The controller/processor240 and/or other processors and modules at the base station 105 mayperform or direct the execution of various processes for the techniquesdescribed herein. The controllers/processor 280 and/or other processorsand modules at the UE 115 may also perform or direct the execution ofthe functional blocks illustrated in FIGS. 5A and 5B, and/or otherprocesses for the techniques described herein. The memories 242 and 282may store data and program codes for the base station 105 and the UE115, respectively. A scheduler 244 may schedule UEs for datatransmission on the downlink and/or uplink.

Wireless communications systems operated by different network operatingentities (e.g., network operators) may share spectrum. In someinstances, a network operating entity may be configured to use anentirety of a designated shared spectrum for at least a period of timebefore another network operating entity uses the entirety of thedesignated shared spectrum for a different period of time. Thus, inorder to allow network operating entities use of the full designatedshared spectrum, and in order to mitigate interfering communicationsbetween the different network operating entities, certain resources(e.g., time) may be partitioned and allocated to the different networkoperating entities for certain types of communication.

For example, a network operating entity may be allocated certain timeresources reserved for exclusive communication by the network operatingentity using the entirety of the shared spectrum. The network operatingentity may also be allocated other time resources where the entity isgiven priority over other network operating entities to communicateusing the shared spectrum. These time resources, prioritized for use bythe network operating entity, may be utilized by other network operatingentities on an opportunistic basis if the prioritized network operatingentity does not utilize the resources. Additional time resources may beallocated for any network operator to use on an opportunistic basis.

Access to the shared spectrum and the arbitration of time resourcesamong different network operating entities may be centrally controlledby a separate entity, autonomously determined by a predefinedarbitration scheme, or dynamically determined based on interactionsbetween wireless nodes of the network operators.

In some cases, UE 115 and base station 105 of the 5G network 100 (inFIG. 1 ) may operate in a shared radio frequency spectrum band, whichmay include licensed or unlicensed (e.g., contention-based) frequencyspectrum. In an unlicensed frequency portion of the shared radiofrequency spectrum band, UEs 115 or base stations 105 may traditionallyperform a medium-sensing procedure to contend for access to thefrequency spectrum. For example, UE 115 or base station 105 may performa listen before talk (LBT) procedure such as a clear channel assessment(CCA) prior to communicating in order to determine whether the sharedchannel is available. A CCA may include an energy detection procedure todetermine whether there are any other active transmissions. For example,a device may infer that a change in a received signal strength indicator(RSSI) of a power meter indicates that a channel is occupied.Specifically, signal power that is concentrated in a certain bandwidthand exceeds a predetermined noise floor may indicate another wirelesstransmitter. A CCA also may include detection of specific sequences thatindicate use of the channel. For example, another device may transmit aspecific preamble prior to transmitting a data sequence. In some cases,an LBT procedure may include a wireless node adjusting its own backoffwindow based on the amount of energy detected on a channel and/or theacknowledge/negative-acknowledge (ACK/NACK) feedback for its owntransmitted packets as a proxy for collisions.

Use of a medium-sensing procedure to contend for access to an unlicensedshared spectrum may result in communication inefficiencies. This may beparticularly evident when multiple network operating entities (e.g.,network operators) are attempting to access a shared resource. In the 5Gnetwork 100, base stations 105 and UEs 115 may be operated by the sameor different network operating entities. In some examples, an individualbase station 105 or UE 115 may be operated by more than one networkoperating entity. In other examples, each base station 105 and UE 115may be operated by a single network operating entity. Requiring eachbase station 105 and UE 115 of different network operating entities tocontend for shared resources may result in increased signaling overheadand communication latency.

FIG. 3 illustrates an example of a timing diagram 300 for coordinatedresource partitioning. The timing diagram 300 includes a superframe 305,which may represent a fixed duration of time (e.g., 20 ms). Thesuperframe 305 may be repeated for a given communication session and maybe used by a wireless system such as 5G network 100 described withreference to FIG. 1 . The superframe 305 may be divided into intervalssuch as an acquisition interval (A-INT) 310 and an arbitration interval315. As described in more detail below, the A-INT 310 and arbitrationinterval 315 may be subdivided into sub-intervals, designated forcertain resource types, and allocated to different network operatingentities to facilitate coordinated communications between the differentnetwork operating entities. For example, the arbitration interval 315may be divided into a plurality of sub-intervals 320. Also, thesuperframe 305 may be further divided into a plurality of subframes 325with a fixed duration (e.g., 1 ms). While timing diagram 300 illustratesthree different network operating entities (e.g., Operator A, OperatorB, Operator C), the number of network operating entities using thesuperframe 305 for coordinated communications may be greater than orfewer than the number illustrated in timing diagram 300.

The A-INT 310 may be a dedicated interval of the superframe 305 that isreserved for exclusive communications by the network operating entities.In some examples, each network operating entity may be allocated certainresources within the A-INT 310 for exclusive communications. Forexample, resources 330-a may be reserved for exclusive communications byOperator A, such as through base station 105 a, resources 330-b may bereserved for exclusive communications by Operator B, such as throughbase station 105 b, and resources 330-c may be reserved for exclusivecommunications by Operator C, such as through base station 105 c. Sincethe resources 330-a are reserved for exclusive communications byOperator A, neither Operator B nor Operator C can communicate duringresources 330-a, even if Operator A chooses not to communicate duringthose resources. That is, access to exclusive resources is limited tothe designated network operator. Similar restrictions apply to resources330-b for Operator B and resources 330-c for Operator C. The wirelessnodes of Operator A (e.g., UEs 115 or base stations 105) may communicateany information desired during their exclusive resources 330-a, such ascontrol information or data.

When communicating over an exclusive resource, a network operatingentity does not need to perform any medium sensing procedures (e.g.,listen-before-talk (LBT) or clear channel assessment (CCA)) because thenetwork operating entity knows that the resources are reserved. Becauseonly the designated network operating entity may communicate overexclusive resources, there may be a reduced likelihood of interferingcommunications as compared to relying on medium sensing techniques alone(e.g., no hidden node problem). In some examples, the A-INT 310 is usedto transmit control information, such as synchronization signals (e.g.,SYNC signals), system information (e.g., system information blocks(SIBs)), paging information (e.g., physical broadcast channel (PBCH)messages), or random access information (e.g., random access channel(RACH) signals). In some examples, all of the wireless nodes associatedwith a network operating entity may transmit at the same time duringtheir exclusive resources.

In some examples, resources may be classified as prioritized for certainnetwork operating entities. Resources that are assigned with priorityfor a certain network operating entity may be referred to as aguaranteed interval (G-INT) for that network operating entity. Theinterval of resources used by the network operating entity during theG-INT may be referred to as a prioritized sub-interval. For example,resources 335-a may be prioritized for use by Operator A and maytherefore be referred to as a G-INT for Operator A (e.g., G-INT-OpA).Similarly, resources 335-b may be prioritized for Operator B (e.g.,G-INT-OpB), resources 335-c (e.g., G-TNT-OpC) may be prioritized forOperator C, resources 335-d may be prioritized for Operator A, resources335-e may be prioritized for Operator B, and resources 335-f may beprioritized for Operator C.

The various G-INT resources illustrated in FIG. 3 appear to be staggeredto illustrate their association with their respective network operatingentities, but these resources may all be on the same frequencybandwidth. Thus, if viewed along a time-frequency grid, the G-INTresources may appear as a contiguous line within the superframe 305.This partitioning of data may be an example of time divisionmultiplexing (TDM). Also, when resources appear in the same sub-interval(e.g., resources 340-a and resources 335-b), these resources representthe same time resources with respect to the superframe 305 (e.g., theresources occupy the same sub-interval 320), but the resources areseparately designated to illustrate that the same time resources can beclassified differently for different operators.

When resources are assigned with priority for a certain networkoperating entity (e.g., a G-INT), that network operating entity maycommunicate using those resources without having to wait or perform anymedium sensing procedures (e.g., LBT or CCA). For example, the wirelessnodes of Operator A are free to communicate any data or controlinformation during resources 335-a without interference from thewireless nodes of Operator B or Operator C.

A network operating entity may additionally signal to another operatorthat it intends to use a particular G-INT. For example, referring toresources 335-a, Operator A may signal to Operator B and Operator C thatit intends to use resources 335-a. Such signaling may be referred to asan activity indication. Moreover, since Operator A has priority overresources 335-a, Operator A may be considered as a higher priorityoperator than both Operator B and Operator C. However, as discussedabove, Operator A does not have to send signaling to the other networkoperating entities to ensure interference-free transmission duringresources 335-a because the resources 335-a are assigned with priorityto Operator A.

Similarly, a network operating entity may signal to another networkoperating entity that it intends not to use a particular G-INT. Thissignaling may also be referred to as an activity indication. Forexample, referring to resources 335-b, Operator B may signal to OperatorA and Operator C that it intends not to use the resources 335-b forcommunication, even though the resources are assigned with priority toOperator B. With reference to resources 335-b, Operator B may beconsidered a higher priority network operating entity than Operator Aand Operator C. In such cases, Operators A and C may attempt to useresources of sub-interval 320 on an opportunistic basis. Thus, from theperspective of Operator A, the sub-interval 320 that contains resources335-b may be considered an opportunistic interval (O-INT) for Operator A(e.g., O-INT-OpA). For illustrative purposes, resources 340-a mayrepresent the O-INT for Operator A. Also, from the perspective ofOperator C, the same sub-interval 320 may represent an O-INT forOperator C with corresponding resources 340-b. Resources 340-a, 335-b,and 340-b all represent the same time resources (e.g., a particularsub-interval 320), but are identified separately to signify that thesame resources may be considered as a G-INT for some network operatingentities and yet as an O-INT for others.

To utilize resources on an opportunistic basis, Operator A and OperatorC may perform medium-sensing procedures to check for communications on aparticular channel before transmitting data. For example, if Operator Bdecides not to use resources 335-b (e.g., G-INT-OpB), then Operator Amay use those same resources (e.g., represented by resources 340-a) byfirst checking the channel for interference (e.g., LBT) and thentransmitting data if the channel was determined to be clear. Similarly,if Operator C wanted to access resources on an opportunistic basisduring sub-interval 320 (e.g., use an O-INT represented by resources340-b) in response to an indication that Operator B was not going to useits G-INT (e.g., resources 335-b), Operator C may perform a mediumsensing procedure and access the resources if available. In some cases,two operators (e.g., Operator A and Operator C) may attempt to accessthe same resources, in which case the operators may employcontention-based procedures to avoid interfering communications. Theoperators may also have sub-priorities assigned to them designed todetermine which operator may gain access to resources if more thanoperator is attempting access simultaneously. For example, Operator Amay have priority over Operator C during sub-interval 320 when OperatorB is not using resources 335-b (e.g., G-INT-OpB). It is noted that inanother sub-interval (not shown) Operator C may have priority overOperator A when Operator B is not using its G-INT.

In some examples, a network operating entity may intend not to use aparticular G-INT assigned to it, but may not send out an activityindication that conveys the intent not to use the resources. In suchcases, for a particular sub-interval 320, lower priority operatingentities may be configured to monitor the channel to determine whether ahigher priority operating entity is using the resources. If a lowerpriority operating entity determines through LBT or similar method thata higher priority operating entity is not going to use its G-INTresources, then the lower priority operating entities may attempt toaccess the resources on an opportunistic basis as described above.

In some examples, access to a G-INT or O-INT may be preceded by areservation signal (e.g., request-to-send (RTS)/clear-to-send (CTS)),and the contention window (CW) may be randomly chosen between one andthe total number of operating entities.

In some examples, an operating entity may employ or be compatible withcoordinated multipoint (CoMP) communications. For example an operatingentity may employ CoMP and dynamic time division duplex (TDD) in a G-INTand opportunistic CoMP in an O-INT as needed.

In the example illustrated in FIG. 3 , each sub-interval 320 includes aG-INT for one of Operator A, B, or C. However, in some cases, one ormore sub-intervals 320 may include resources that are neither reservedfor exclusive use nor reserved for prioritized use (e.g., unassignedresources). Such unassigned resources may be considered an O-INT for anynetwork operating entity, and may be accessed on an opportunistic basisas described above.

In some examples, each subframe 325 may contain 14 symbols (e.g., 250-μsfor 60 kHz tone spacing). These subframes 325 may be standalone,self-contained Interval-Cs (ITCs) or the subframes 325 may be a part ofa long ITC. An ITC may be a self-contained transmission starting with adownlink transmission and ending with a uplink transmission. In someembodiments, an ITC may contain one or more subframes 325 operatingcontiguously upon medium occupation. In some cases, there may be amaximum of eight network operators in an A-INT 310 (e.g., with durationof 2 ms) assuming a 250-μs transmission opportunity.

Although three operators are illustrated in FIG. 3 , it should beunderstood that fewer or more network operating entities may beconfigured to operate in a coordinated manner as described above. Insome cases, the location of the G-INT, O-INT, or A-INT within superframe305 for each operator is determined autonomously based on the number ofnetwork operating entities active in a system. For example, if there isonly one network operating entity, each sub-interval 320 may be occupiedby a G-INT for that single network operating entity, or thesub-intervals 320 may alternate between G-INTs for that networkoperating entity and O-INTs to allow other network operating entities toenter. If there are two network operating entities, the sub-intervals320 may alternate between G-INTs for the first network operating entityand G-INTs for the second network operating entity. If there are threenetwork operating entities, the G-INT and O-INTs for each networkoperating entity may be designed as illustrated in FIG. 3 . If there arefour network operating entities, the first four sub-intervals 320 mayinclude consecutive G-INTs for the four network operating entities andthe remaining two sub-intervals 320 may contain O-INTs. Similarly, ifthere are five network operating entities, the first five sub-intervals320 may contain consecutive G-INTs for the five network operatingentities and the remaining sub-interval 320 may contain an O-INT. Ifthere are six network operating entities, all six sub-intervals 320 mayinclude consecutive G-INTs for each network operating entity. It shouldbe understood that these examples are for illustrative purposes only andthat other autonomously determined interval allocations may be used.

It should be understood that the coordination framework described withreference to FIG. 3 is for illustration purposes only. For example, theduration of superframe 305 may be more or less than 20 ms. Also, thenumber, duration, and location of sub-intervals 320 and subframes 325may differ from the configuration illustrated. Also, the types ofresource designations (e.g., exclusive, prioritized, unassigned) maydiffer or include more or less sub-designations.

In sub-7 GHz NR networks, the channel bandwidth can be up to 100 MHz.This channel bandwidth feature for NR networks may be extended to NRunlicensed (NR-U) networks as well. On the other side of the spectrum,the features of 5G NR/NR-U networks have been developed to alsoaccommodate communications of low-RF-capable UEs, such as a devicelimited to 20 MHz RF coverage. The concept of bandwidth part (BWP) wasincluded for NR/NR-U operations to facilitate support to theselow-RF-capable UEs. However, considering the wide range of bandwidthsavailable, listen before talk (LBT) operations in NR-U may imposechallenges for detecting truly available shared spectrum. In order toco-exist with WiFi and license assisted access (LAA) networks, NR-Unodes conduct LBT procedures using a 20 MHz granularity (e.g., at an LBTsubband). The dynamic/chaotic unlicensed deployment of NR-U operationsgenerally leads to the node checking availability of various anunpredictable numbers of such LBT subbands for each TxOP. Moreover, theparticular LBT subband to be monitored is, in general, unpredictablewithout a specific arrangement of the LBT structure in a multi-channelaccess environment. Low-RF-capable UEs monitoring a specific subband maylose access opportunities in the current transmission opportunity(TxOP)), which can become a significant issue when a base station or anoperator is serving only low-RF-capable UEs. One extreme solution hasbeen suggested to simply disable multi-channel access for thisparticular base station or operator. Unfortunately this may cause anunfairness in access to the shared spectrum.

FIG. 4A is a block diagram illustrating NR-U network 40. NR-U network 40provides access to a communication spectrum that may be shared byvarious radio access technologies on an unlicensed basis. Within accesscompetition between both low-RF-capable and higher-RF-capable devices oftwo different operators (OP 1 and OP 2), such as low-RF-capable UE 115 fand UE 115 b, the LBT configuration of each communication pair (e.g.,base station 105 a and low-RE-capable UE 115 f of OP 1, base station 105b and UE 115 b of OP 2) may impact the rate of successful access foreach node. For example, as illustrated in FIG. 4A, the LBT configurationof OP 1 provides for its only channel, f1, as the primary channel, whilethe LBT configuration of OP 2 provides the primary channel as f1 and thesecondary channel as f2. Thus, each of OP 1 and OP2 have the samechannel frequency for their respective primary channels. Such aco-primary configuration generally results in lower performance forcommunications between base station 105 a and low-RF-capable UE 115 f ofOP1 than between base station 105 b and 115 b of OP 2.

FIG. 4B is a block diagram illustrating NR-U network 41. As illustrated,the LBT configuration of OP 1 provides for f1 as the primary channel,while the LBT configuration of OP 2 provides the primary channel of f2and secondary channel of f1. As such, the primary channels between OP 1and OP 2 are interleaved, which gives communications between basestation 105 a and 115 f of OP 1 a higher probability of success, whilestill providing communication opportunities for base station 105 b andUE 115 b of OP 2. OP 1 may strongly favor no sharing of spectrum with OP2 at all, unless a fairness restriction exists to ensure OP 1accessibility. Thus, OP 1 may favor disabling such multi-channel accesswhen multiple operators compete for the same communication spectrum.

Various aspects of the present disclosure are directed to enabling ormaintaining multi-channel access when single operator operations cannotbe guaranteed. The long-term presence of another operator can detectedthrough the reading of WiFi beacons and LAA or NR-U nodes' discoveryreference signals (DRS). Furthermore, the short-term presence of WiFinodes around LAA and NR-U nodes can also be detected through shorttraining field (STF) correlation as found in WiFi preamble signals. TheNR-U networks defines the primary and secondary channels, signalslow-RF-capable UEs to monitor the primary for LBT clear signals, andthen directs the low-RF-capable UEs to re-tune to the secondary channelfor communications after the secondary channel is secured by the NR-Ubase station.

FIG. 5A is a block diagram illustrating example blocks executed by abase station to implement one aspect of the present disclosure. Theexample blocks will also be described with respect to base station 105as illustrated in FIG. 7 . FIG. 7 is a block diagram illustrating basestation 105 configured according to one aspect of the presentdisclosure. Base station 105 includes the structure, hardware, andcomponents as illustrated for base station 105 of FIG. 2 . For example,base station 105 includes controller/processor 240, which operates toexecute logic or computer instructions stored in memory 242, as well ascontrolling the components of base station 105 that provide the featuresand functionality of base station 105. Base station 105, under controlof controller/processor 240, transmits and receives signals via wirelessradios 700 a-t and antennas 234 a-t. Wireless radios 700 a-t includesvarious components and hardware, as illustrated in FIG. 2 for basestation 105, including modulator/demodulators 232 a-t, MIMO detector236, receive processor 238, transmit processor 220, and TX MIMOprocessor 230.

At block 500, a base station enables multi-channel access when singleoperator operations cannot be guaranteed within a shared communicationspectrum. Base station, such as base station 105, of a given operatormay detect either the long-term or short-term presence of otheroperators within its coverage area of the shared communication spectrum.For example, various interference signals may be received at basestation 105 via antennas 234 a-t and wireless radios 700 a-t which,under control of controller/processor 240, are determined to originatefrom interfering transmitters associated with other operators. As suchother operators are detected, base station 105 executes multi-channeloperations feature 701, in memory 242. The execution environment ofmulti-channel operations feature 701 ensures that multi-channel accessis enabled or maintained for its served UEs.

At block 501, the base station defines a primary channel and a secondarychannels within the shared communication channel. For example, basestation 105, under control of controller/processor 240, executes accessconfiguration logic 702, stored in memory 242. The execution environmentof access configuration logic 702 provides for base station 105 toselect an LBT configuration for the TxOP that identities the primary andsecondary channels in the shared spectrum.

At block 502, the base station transmits a configuration message to oneor more low-RF UEs, wherein the configuration message configures the oneor more low-RF UEs to monitor the primary channel for a successful LBTindicator. Within the execution environment of access configurationlogic 702, base station 105 transmits a configuration message viawireless radios 700 a-t and antennas 234 a-t to each of its servedlow-RF-capable UEs. The configuration message identifies the primary andsecondary LBT channels and directs the UEs to monitor the primarychannel for results of an LBT procedure (e.g., extended clear channelassessment (ECCA), clear channel assessment (CCA), and the like).

At block 503, the base station performs an LBT procedure on the primarychannel and the secondary channel. Base station 105, under control ofcontroller processor 240, executes LBT procedures 703, stored in memory242. The execution environment of LBT procedures 703 provides thefunctionally for base station 105 to perform an LBT procedure. Forexample, the execution environment of LBT procedure 703 allows basestation 105 to perform an ECCA on the primary channel and a CCA on thesecondary channel prior to initiating further communications. As isknown in the art, such LBT procedures may be based on energy detection,preamble detection, or the like.

At block 504, the base station signals the low-RF UEs on the primarychannel to re-tune to the secondary channel for communication during acurrent transmission opportunity in response to success of the LBTprocedure on the secondary channel. If the LBT procedures are successfulon both the primary and secondary channels, base station 105, undercontrol of controller/processor 240, executes re-tuning logic 704,stored in memory 242. The execution environment of re-tuning logic 704provides the functionality to base station 105 to transmit signals tothe low-RF UEs via wireless radios 700 a-t and antennas 234 a-t tore-tune to the secondary channel for communications. The re-tuningsignal may be issued in the form of commands from base station 105, suchas a downlink control information (DCI) signal, over the primary channelto the low-RF UEs to re-tune to the secondary channel or channels forcommunications in the current TxOP. In order to maintain access to thesecondary channel, within the execution environment of re-tuning logic704, base station 105 may perform a reserving function on the secondarychannel, such as by transmitting a filler or occupancy signal ortransmitting a reservation signal (e.g., RTS/CTS) on the secondarychannel via wireless radios 700 a-t and antennas 234 a-t.

FIG. 5B is a block diagram illustrating example blocks executed by alow-RE-capable UE to implement one aspect of the present disclosure. Theexample blocks will also be described with respect to UE 115 asillustrated in FIG. 8 . FIG. 8 is a block diagram illustrating UE 115configured according to one aspect of the present disclosure. UE 115includes the structure, hardware, and components as illustrated for UE115 of FIG. 2 . For example, UE 115 includes controller/processor 280,which operates to execute logic or computer instructions stored inmemory 282, as well as controlling the components of UE 115 that providethe features and functionality of UE 115. UE 115, under control ofcontroller/processor 280, transmits and receives signals via wirelessradios 800 a-r and antennas 252 a-r. Wireless radios 800 a-r includesvarious components and hardware, as illustrated in FIG. 2 for UE 115,including modulator/demodulators 254 a-r, MIMO detector 256, receiveprocessor 258, transmit processor 264, and TX MIMO processor 266.

At block 505, the low-RF UE receives a configuration message from aserving base station. A low-RF UE, such as UE 115, receives theconfiguration message from the serving base station via antennas 252 a-rand wireless radios 800 a-r and stores it at access configuration 801 inmemory 282. The configuration message identifies the primary andsecondary LBT channels of the shared spectrum and directs the low-RF UEto monitor the primary channel for results of an LET procedure.

At block 506, the low-RF UE monitors the primary channel for a LBTindicator in response to the configuration message. With the limited RFcapabilities, the low-RF-capable UEs, UE 115, monitor the primarychannel using antennas 252 a-r and wireless radios 800 a-r forindications of a successful LBT, such as an ECCA, CCA, etc.

At block 507, the low-RF UE receives a re-tuning signal on the primarychannel, wherein the re-tuning signal instructs the low-RF UE to re-tuneto a secondary channel for communications during the currenttransmission opportunity. When the indication of successful LBT isdetected via antennas 252 a-r and wireless radios 800 a-r, the low-RFUE, UE 115, will further receive a re-tuning signal from the servingbase station via antennas 252 a-r and wireless radios 800 a-r. There-tuning signal, which may be included in a DCI message, instructs UE115 to re-tune wireless radios 800 a-r to the secondary channel, asindicated in access configuration 801. UE 115 would then re-tunewireless radios 800 a-r to the secondary channel for communications(e.g., uplink or downlink) during the current TxOP. These low-RF UEs,such as UE 115, will tune wireless radios 800 a-r back to monitor theprimary channel after the current TxOP ends.

It should be noted that the various aspects of the present disclosureare not limited to a DCI based approach for signaling the re-tuning oflow-RF UEs, such as UE 115. Any delay that might be associated with DCIsignaling may be reduced by providing an embedded indicator into thepreamble at the beginning of the TxOP. Such an aspect would be usefulwhere UE 115 is capable of performing hard-decoding over the preamble.The number of signaling bits can be reduced by pre-allocating thecandidate secondary channel(s) to each low-RF-capable UE, such as UE115, through prior RRC signaling. For example, a one-bit indication maybe sufficient to allocate UE 115 to a pre-defined, pre-allocatedsecondary channel.

FIGS. 6A-6D are block diagrams illustrating multi-channel communicationsbetween a base station 105 a and a low-RF UE 115 f each configuredaccording to aspects of the present disclosure. In each of FIGS. 6A-6D,base station 105 a communicates with low-RF UE 115 f using primarychannel 60 and secondary channel 61. After configuring the sharedspectrum to select the frequencies of primary channel 60 and secondarychannel 61, base station 105 a transmits the LBT configuration to low-RFUE 115 f and instructs low-RF UE 115 f to monitor primary channel 60 foridentification of successful LET results. Ease station 105 performs ECCA600 on primary channel 60 to secure access, while performing CCA 601 onsecondary channel 61. When both ECCA 600 and CCA 601 are detected assuccessful, base station 105 a will signal low-RF UE 115 f to re-tune tosecondary channel 61. Base station 105 a may then use differentmechanisms to maintain reservation of secondary channel 61.

As illustrated in FIGS. 6A and 6B, base station 105 a uses a fillertransmission 602 to maintain occupation of secondary channel 61. Afterdetecting successful completion of ECCA 600 and CCA 601, base station105 a signals low-RF UE 115 f to re-tune to secondary channel 61, asnoted above. After transmitting this signaling, which may be part of aDCI or a signal in the TxOP preamble, low-RF UE 115 f begins there-tuning processor. During that time, in order to prevent a neighboringcell from occupying secondary channel 61, base station 105 a willtransmit filler transmission 602 on secondary channel 61. Fillertransmission 602 will occupy or reserve secondary channel 61, such thatany neighboring cells that may attempt LBT during that time, will beblocked from transmissions. Thereafter, in FIG. 6A, base station 105 amay transmit downlink 603 to any other non-low-RF UEs via primarychannel 60, and transmit downlink 604 to low-RF UE 115 f via secondarychannel 61. In FIG. 6B, base station 105 a may transmit downlink 605 andreceive uplink 606 on primary channel 60 with a non-low-RF UE, andreceive uplink 607 on secondary channel 61 from low-RF UE 115 f.

As illustrated in FIGS. 6C and 6D, base station 105 a uses a channelreservation signal to maintain occupation of secondary channel 61. Thechannel reservation signal used by base station 105 a in FIGS. 6C and 6Dis a request-to-send (RTS) 608 or clear-to-send (CTS) 613. RTS/CTSsignaling can effectively operate to keep neighboring nodes fromattempting access to secondary channel 61. In such cases, a related CTS609 may or may not be transmitted on primary channel 60. RTS 608/CTS 613on secondary channel 61 are transmitted for any neighboring nodelistening or available for sharing the shared spectrum of secondarychannel 61. Once detected by the neighboring node, the neighboring nodemay be configured to delay attempted access to secondary channel 61 to anext transmission availability or TxOP. Thereafter, in FIG. 6C, basestation 105 a may participate in uplink 610 and downlink 611 on primarychannel 60 with other non-low-RF UEs and transmit downlink 612 to low-RFUE 115 f via secondary channel 61. In FIG. 6D, base station 105 a mayreceive uplink 614 on primary channel 60 from a non-low-RF UE andreceive uplink 615 from low-RF UE 115 f via secondary channel 61.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

The functional blocks and modules in FIGS. 5A and 5B may compriseprocessors, electronics devices, hardware devices, electronicscomponents, logical circuits, memories, software codes, firmware codes,etc., or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the disclosure herein may be implemented as electronichardware, computer software, or combinations of both. To clearlyillustrate this interchangeability of hardware and software, variousillustrative components, blocks, modules, circuits, and steps have beendescribed above generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure. Skilled artisans will also readilyrecognize that the order or combination of components, methods, orinteractions that are described herein are merely examples and that thecomponents, methods, or interactions of the various aspects of thepresent disclosure may be combined or performed in ways other than thoseillustrated and described herein.

The various illustrative logical blocks, modules, and circuits describedin connection with the disclosure herein may be implemented or performedwith a general-purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Ageneral-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thedisclosure herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such that theprocessor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a user terminal. In the alternative, theprocessor and the storage medium may reside as discrete components in auser terminal.

In one or more exemplary designs, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another.Computer-readable storage media may be any available media that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, such computer-readable media can compriseRAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic diskstorage or other magnetic storage devices, or any other medium that canbe used to carry or store desired program code means in the form ofinstructions or data structures and that can be accessed by ageneral-purpose or special-purpose computer, or a general-purpose orspecial-purpose processor. Also, a connection may be properly termed acomputer-readable medium. For example, if the software is transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, or digital subscriber line (DSL), thenthe coaxial cable, fiber optic cable, twisted pair, or DSL, are includedin the definition of medium. Disk and disc, as used herein, includescompact disc (CD), laser disc, optical disc, digital versatile disc(DVD), floppy disk and blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer-readable media.

As used herein, including in the claims, the term “and/or,” when used ina list of two or more items, means that any one of the listed items canbe employed by itself, or any combination of two or more of the listeditems can be employed. For example, if a composition is described ascontaining components A, B, and/or C, the composition can contain Aalone; B alone; C alone; A and B in combination; A and C in combination;B and C in combination; or A, B, and C in combination. Also, as usedherein, including in the claims, “or” as used in a list of itemsprefaced by “at least one of” indicates a disjunctive list such that,for example, a list of “at least one of A, B, or C” means A or B or C orAB or AC or BC or ABC (i.e., A and B and C) or any of these in anycombination thereof.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method of wireless communication, the methodcomprising: transmitting, by a network equipment, a configurationmessage to one or more low-radio frequency (RF) user equipments (UEs),wherein the configuration message is associated with configuring the oneor more low-RF UEs to monitor a primary channel of a sharedcommunication spectrum for a successful listen before talk (LBT)indicator, the shared communication spectrum including the primarychannel and a secondary channel defined by the network equipment;performing, by the network equipment, an LBT procedure on the primarychannel and the secondary channel; and signaling, by the networkequipment and during a transmission opportunity, the one or more low-RFUEs on the primary channel to re-tune from the primary channel to thesecondary channel for communication during the transmission opportunitybased on success of the LBT procedure on both the primary and secondarychannels.
 2. The method of claim 1, wherein the network equipmentcomprises a base station and further including: transmitting, by networkequipment during the transmission opportunity, a reservation signal onthe secondary channel during a re-tuning period of the one or morelow-RF UEs.
 3. The method of claim 2, wherein the reservation signalincludes: a clear-to-send (CTS) signal; a request-to-send (RTS) signal;or a channel occupancy signal.
 4. The method of claim 1, wherein thesignaling includes signaling on a downlink control signal to re-tune; orembedding a re-tuning signal into a preamble at a beginning of thetransmission opportunity.
 5. The method of claim 4, wherein theconfiguration message further includes a pre-allocation location of thesecond channel to the one or more low-RF UEs, and wherein the re-tuningsignal signals the one or more low-RF UEs to re-tune to the secondchannel at the pre-allocation location.
 6. The method of claim 1,further comprising: enabling, by the network equipment, multi-channelaccess based on single operator operations being unguaranteed within theshared communication spectrum; and defining, by the network equipment,the primary channel and the secondary channels within the sharedcommunication channel; and prior to transmission of the configurationmessage, transmitting an indication of an allocation of the secondarychannel as a candidate secondary channel to the one or more low-RF UEs,and wherein at least one low-RF UE of the one or more low-RF UEs has amaximum channel bandwidth capability of 20 MHz.
 7. The method of claim1, further comprising: selecting a set of one or more candidatesecondary channels, the set of candidate secondary channels includingthe secondary channel; and wherein performing the LBT procedure on theprimary channel and the secondary channel includes: performing anextended clear channel assessment (ECCA) on the primary channel; andperforming a clear channel assessment (CCA) on each secondary channel ofthe set of candidate secondary channels.
 8. A method of communication,comprising: receiving, by a low-radio frequency (RF) user equipment(UE), a configuration message from a serving network equipment;monitoring, by the low-RF UE and based on the configuration message, aprimary channel for a successful listen before talk (LBT) indicator; andreceiving, by the low-RF UE during a transmission opportunity, are-tuning signal on the primary channel, wherein the re-tuning signalinstructs the low-RF UE to re-tune, during the transmission opportunity,from the primary channel to a secondary channel for communicationsduring the transmission opportunity; wherein: the re-tuning signal isreceived in response to a successful listen before talk (LBT) procedureperformed on the primary channel and on the secondary channel, theprimary channel and the secondary channel are included within a sharedcommunication spectrum, and the re-tuning signal is received via adownlink control signal of the re-tuning signal is embedded into apreamble received at a beginning of the transmission opportunity.
 9. Themethod of claim 8, further including: communicating with the servingnetwork equipment on the secondary channel during the transmissionopportunity; and tuning, by the low-RF UE, back to the primary channelafter the transmission opportunity.
 10. The method of claim 8, whereinthe configuration message pre-allocates one or more secondary channelsto the low-RF UE, and wherein the re-tuning signal identifies thesecondary channel from the pre-allocated one or more secondary channels.11. A network equipment configured for wireless communication, thenetwork equipment comprising: at least one processor; and a memorycoupled to the at least one processor and storing processor-readablecode that, when executed by the processor, is configured to: transmit aconfiguration message to one or more low-radio frequency (RF) userequipments (UEs), wherein the configuration message configures the oneor more low-RF UEs to monitor the primary channel for a successfullisten before talk (LBT) indicator; perform an LBT procedure on theprimary channel and a secondary channel; and signal the one or morelow-RF UEs on the primary channel to re-tune to the secondary channelfor communication during a transmission opportunity based on success ofthe LBT procedures on both the primary and secondary channels.
 12. Thenetwork equipment of claim 11, wherein the processor-readable code that,when executed by the at least one processor, is further configured toinitiate transmission of a reservation signal on the secondary channelduring a re-tuning period of the one or more low-RF UEs.
 13. The networkequipment of claim 12, wherein the reservation signal includes: aclear-to-send (CTS) signal; a request-to-send (RTS) signal; or a channeloccupancy signal.
 14. The network equipment of claim 11, wherein, tosignal the one or more low-RF UEs on the primary channel to re-tune tothe secondary channel, the processor-readable code that, when executedby the at least one processor, is further configured to: signal on adownlink control signal to re-tune; or embed a re-tuning signal into apreamble at a beginning of the transmission opportunity.
 15. The networkequipment of claim 14, wherein the configuration message furtherincludes a pre-allocation location of the secondary channel to the oneor more low-RF UEs, and wherein the re-tuning signal signals the one ormore low-RF UEs to re-tune to the secondary channel at thepre-allocation location.
 16. A low-radio frequency (RF) user equipment(UE) configured for wireless communication, the low-RF UE comprising: atleast one processor; and a memory coupled to the at least one processorand storing processor-readable code that, when executed by theprocessor, is further configured to: receive a configuration messagefrom a serving network equipment; monitor a primary channel for asuccessful listen before talk (LBT) indicator based on the configurationmessage; and receive, during a transmission opportunity, a re-tuningsignal on the primary channel, wherein the re-tuning signal instructsthe low-RF UE to re-tune, during the transmission opportunity from theprimary channel to a secondary channel for communications during thetransmission opportunity; wherein the re-tuning signal is received inresponse to a successful listen before talk (LBT) procedure performed onthe primary channel and on the secondary channel, the primary channeland the secondary channel are included within a shared communicationspectrum, and the re-tuning signal is received via a downlink controlsignal or the re-tuning signal is embedded into a preamble received at abeginning of the transmission opportunity.
 17. The low-RF UE of claim16, wherein the processor-readable code that, when executed by the atleast one processor, is further configured to tune back to the primarychannel after the transmission opportunity.
 18. The low-RF UE of claim16, wherein the re-tuning signal is received via: a downlink controlsignal; or embedded into a preamble received at a beginning of thetransmission opportunity.
 19. The low-RF UE of claim 18, wherein theconfiguration message pre-allocates one or more secondary channels tothe low-RF UE, and wherein the re-tuning signal identifies the secondarychannel from the pre-allocated one or more secondary channels.